The invention relates to improvements in axial- and mixed-flow centrifugal pumps in general, and more particularly to improvements in impellers for use in such pumps. Still more particularly, the invention relates to improvements in the vanes of impellers for use in axial- or mixed-flow centrifugal pumps.
Centrifugal pumps are used for the conveying of fluids which are devoid of solid particles as well as for the conveying of fluids, particularly liquids, which are laden with impurities. Problems arise when the conveyed fluid media contain relatively large quantities of elongated flexible bodies such as strips or strands of plastic material, grass and the like. Elongated flexible bodies tend to gather on the inlet edges of the vanes and to rapidly clog the impeller so as to necessitate an interruption of the operation. The impeller becomes inoperative after a relatively short period of use (e.g., within minutes), especially if the fluid medium contains a large quantity of strip-shaped or like flexible material.